The Saudi Arabian ambassador to the U.S. said Wednesday that the Houthi rebels in Yemen have no choice but to give up their fight to take over the country by force.

Ambassador Adel al-Jubeir said the Saudi-led Arab coalition would make sure the Houthis fail.

"The kingdom of Saudi Arabia is Yemen's best friend," he said at a Washington news conference. "We have no ambitions in Yemen, territorial or otherwise. ... We want to have a stable, secure, prosperous Yemen, because that has a positive impact on Saudi Arabia."

Jubier said that the Saudis were starting to see cracks in the Houthi leadership and that some Houthis had defected back to the regular Yemeni army.

"We expect to see more and more of them as pressure intensifies," he said. "This operation will continue until objectives are achieved. There can be no half measures."

Jubier denied U.N. allegations that the Saudi-led airstrikes had been indiscriminate and had killed a large number of civilians.

When asked about five shiploads of badly needed food and humanitarian supplies reportedly sitting off the Yemeni coast, the ambassador said the ships entering the port had to be searched for weapons.

The Saudis and their Gulf allies launched the airstrikes on the Iranian-backed Houthi rebels in Yemen three weeks ago. They are looking to restore the internationally recognized government of President Abd-Rabbu Mansour Hadi.